It has heretofore been proposed as disclosed in U.S. Pat. Nos. 4,316,493 and 4,214,622, to make a vertical venetian blind with a wand type operator arranged so that pulling the wand operator lengthwise of the headrail effects traversing of the slat carriages along the headrail and rotation of the wand at any point along the headrail effected turning of the vertical blind slats. In the above patents, the slat carriers and the axis of rotation of the wand connection to the rotation control is offset from a central vertical plane through the headrail so that it was necessary to assemble the slat carriages and control carriage in one arrangement for use in installations in which the slats would stack at the left and in a different arrangement for installations in which the slats would stack at the right. In the '493 patent, the slat carriers were also rotatable about axes disposed in a different longitudinal plane than the wand control shaft such that the wand control shaft would interfere with closing of the slats in one direction.